PARKLAND, Fla. (Reuters) - A teenager accused of fatally shooting 17 people at a Florida high school was investigated by police and state officials as far back as 2016 after slashing his arm in a social media video, and saying he wanted to buy a gun, but authorities determined he was receiving sufficient support, newspapers said on Saturday.

WASHINGTON (Reuters) - A Russian propaganda arm oversaw a criminal and espionage conspiracy to tamper in the 2016 U.S. presidential campaign to support Donald Trump and disparage Hillary Clinton, said an indictment released on Friday that revealed more details than previously known about Moscow's purported effort to interfere.

WASHINGTON (Reuters) - Former Trump campaign chairman Paul Manafort has drawn a new accusation of bank fraud from U.S. Special Counsel Robert Mueller's office, according to court documents made public on Friday.

MIAMI (Reuters) - Student survivors of a mass shooting that killed 17 people at a Florida high school called for gun restrictions on Saturday during an angry and somber rally, but attendees at a nearby gun show said firearms could not be blamed for the massacre.

WASHINGTON (Reuters) - Facebook Inc will start using postcards sent by U.S. mail later this year to verify the identities and location of people who want to purchase U.S. election-related advertising on its site, a senior company executive said on Saturday.

SAN FRANCISCO/WASHINGTON (Reuters) - The Russian influence operation designed to tamper with the 2016 U.S. presidential election used a combination of old-school espionage tactics and 21st-century technologies that will not be easy to stop, even now that the methods have been exposed, experts said.

MAGNITOGORSK, Russia (Reuters) - Unknown hackers stole 339.5 million roubles ($6 million) from a Russian bank last year in an attack using the SWIFT international payments messaging system, the Russian central bank said on Friday.

BRUSSELS (Reuters) - A Belgian court threatened Facebook on Friday with a fine of up to 100 million euros ($125 million) if it continued to break privacy laws by tracking people on third-party websites.